Transcript The Midlatitude Cyclone

The Midlatitude Cyclone
Cyclone Development
begins with a
stationary front
Before Birth
Forecasting where on the
Stationary front the development
will occur is the tricky part!
Nascent stage of
Cyclone Development
Birth and
adolescence
Mature stage
of Cyclone
Development
Adulthood
Mature Wave Cyclone
Typical Cold Front Structure
• Cold air replaces warm; leading edge is steep in fast-moving
front shown below due to friction at the ground
– Strong vertical motion and unstable air forms cumuliform clouds
– Upper level winds blow ice crystals downwind creating cirrus and
cirrostratus. Note change in wind and temperature as front passes.
• Slower moving fronts have less steep boundaries and less
vertically developed clouds may form if warm air is stable
Typical Warm Front Structure
• In an advancing warm front, warm air rides up over colder air at the
surface; slope is not usually very steep
• Lifting of the warm air produces clouds and precipitation well in
advance of boundary
• At different points along the warm/cold air interface, the precipitation
will experience different temperature histories as it falls to the ground
The Partially Occluded
Stage begins
when the cold front
starts to overrun the
warm front
Middle age
Partially occluded wave cyclone
• Cold-occluded front
– Approach brings
weather sequence
like a warm front
– Frontal passage
brings weather more
like a cold front
• Warm-occluded
fronts also possible
Cold-occluded front
Relationship between occluded fronts and
Midlatitude cyclone development
Mature wave
cyclone
Partially occluded
wave cyclone
The Occluded Stage
is characterized by
more warm air
being pushed aloft
and the size of the
warm air wedge
at the surface
decreases significantly
Over the
Hill
Relationship between occluded fronts and a
Midlatitude cyclone
Partially occluded
wave cyclone
Occluded wave
cyclone
The final decay stage
of the cyclone. The warm
air is isolated aloft with
cold air beneath.
Death
The Wave Cyclone Model
(Norwegian model)
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Stationary Front
Nascent Stage
Mature Stage
Partially Occluded Stage
Occluded Stage
Dissipated Stage